SPECIFIC RESEARCH GOALS: 1) To determine the response to skin oxygen tension in clinically encountered low-flow states and 2) to attempt to base the resuscitation regime of peritonitis on a physiologic basis by investigating albumin kinetics in the normal state and during peritonitis and resuscitation. During the current year the first project completed demonstrated that transcutaneous oxygen measurements are a sensitive, non-invasive indicator of low-flow states induced by hemorrhage and the adequacy of resuscitation. A second project soon to be completed indicates that in the injured lung high levels of continuous positive airway pressure are effective in increasing arterial oxygen tension but that transcutaneous oxygen does not rise significantly so that a large discrepancy exists between PaO2 and TcPO2. The study of albumin kinetics in normal piglets and piglets suffering from peritonitis, using I131 and I125 tagged albumin is 75% completed. The data suggests that with peritonitis albumin moves from the blood into the peritoneal cavity and retroperitoneal tissues but albumin in the peritoneal cavity is only minimally absorbed into the circulation. These findings lend support to the concept that peritonitis includes a severe mesothelial cell injury which results in loss of the ability of the peritoneal cells to transfer albumin across the peritoneal membrane to the lymphatics and then to the blood.